A variety of evidence suggests that human vocabulary acquisition and verbal short-term ability are related. The aim of this study was to investigate the learning of new lexical and semantic representation in 7 to 12 years old children selected on the basis of their poor working memory capacity. A deep characterization of the short-term memory (STM) capacities has been carried out through a series of tasks derived from recent STM models tapping STM, language and attentional processes. Participants experienced a three conditions word learning task designed to reflect lexical learning, semantic learning and lexical–semantic learning capacities. Other aspects of the learning such as the learning rate and the word length effect were evaluated. The experimental participants scored more poorly than controls on lexical learning, and this deficit was associated with the serial order STM and the attentional capacities. The current study also highlighted that neither the experimental group nor the control group took advantage in lexical learning of semantic information supplement. Our results suggest that children with verbal STM problems learn a smaller number of new words but present a similar way of learning than children without verbal STM problems. Copyright © 2013 John Wiley & Sons, Ltd.